A recessed lighting fixture is a light fixture that is installed in a hollow opening in a ceiling. A typical recessed lighting fixture includes hanger bars fastened to spaced-apart ceiling supports or joists. A plaster frame extends between the hanger bars and includes an aperture configured to receive a lamp housing or “can.” A bottom edge of an installed can should be flush with a bottom edge of the ceiling. Thus, the bottom of the installed lighting fixture is mounted flush with the visible surface of the ceiling, and the body of the lighting fixture projects into the space above the ceiling.
Because these recessed fixtures are in contact with, or very close to, the ceiling and joists the temperature of the portions of the fixture that will come into contact with any flammable materials must be maintained below acceptable levels. Standards have been created that set forth the acceptable temperature levels for different portions of the recessed fixture. Typically, those portions of the recessed fixture in contact with or very close to the ceiling or joists must maintain a temperature at those contact points that is below ninety degrees Celsius. For recessed lighting fixtures that will come into contact with insulation, called insulation contact or “IC” fixtures, the portions of the fixture that are in contact with the insulation also must be maintained below these acceptable temperature levels. Furthermore, for IC recessed fixtures, the can cannot directly vent thermal energy into the area above the ceiling.
Conventional fixtures have included many methods to distribute thermal energy to prevent the recessed fixture from having a temperature above acceptable levels. For instance, some conventional recessed fixtures have a can that is “closed” at the top and open at the bottom to direct the thermal energy downward below the ceiling and into the room environment. Other conventional recessed fixtures improved on this by placing a domed top on the can to increase the surface area of the can for the dispersion of thermal energy that is not directed down and out of the can. Unfortunately, for many lamps having higher wattage output (and therefore higher levels of thermal energy) a closed can is not able to adequately disperse the thermal energy and maintain a temperature below the acceptable level, especially at the top of the can and along the trim where it contacts the ceiling.
To overcome this problem, some conventional recessed fixtures replaced the closed can with an “open” can, having openings at both the top and the bottom of the can. Furthermore, since the thermal energy could not be directly vented into the ceiling, an air-tight housing was placed around the portion of the can above the ceiling level. While the open can recessed fixture provided improved thermal characteristics, by drawing the thermal energy up through the can and into the housing through convection and radiation, for higher wattage lamps, the top of the housing typically reached temperature levels that were still above the acceptable level because an inordinate amount of thermal energy was directly transmitted to the top of the housing through convection in the open can. Conventional methods for solving this problem include making the housing big enough such that it has sufficient surface area to distribute the heat and maintain the exterior surfaces below the acceptable levels. However, larger housings take up larger spaces in the ceiling area, are bulkier to install and are generally not favored. Furthermore, in many residential applications, one or more dimensions of the housing are restricted based on the distance between the joists or the distance between the ceiling and the roof structure.
Therefore, a need exists in the art for recessed lighting fixtures using higher wattage lamps to safely and efficiently distribute thermal energy and maintain exterior surfaces below acceptable levels. In particular, a need exists in the art for cost-efficient systems and methods for providing IC recessed lighting fixtures capable of efficiently distributing thermal energy while maintaining exterior surfaces of the fixture below acceptable levels in a housing having a relatively small volume.